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06-13-2016, 03:25 PM   #31
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QuoteOriginally posted by bessa-66 Quote
Does the 300mm give a 400mm field of view on the Kx even though it's a DA digital lens?
Yes. Here are some additional characters so that the forum will accept "yes" for an answer.

06-14-2016, 12:53 AM   #32
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QuoteOriginally posted by Quartermaster James Quote
Yes. Here are some additional characters so that the forum will accept "yes" for an answer.
I see. I that was only with old film lenses though. Good stuff anyway- I like the 300mm focal length!
06-14-2016, 06:59 AM   #33
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QuoteOriginally posted by stevebrot Quote
Other way around for the "A" contact. What you are describing is related to the "data" pin*. The camera will test for continuity between that pin on the body and the lens mount as a means of telling whether a lens is mounted and will gate some functions based on the result.


Steve

* The "A" pin is at position #3, while the "data" or "digital contact information" pin is at position #7 See article HERE
Thanks, sorry, used wrong name.
I noticed that some of my older lens-issues were resolved simple by making these contacts work again (or in case of some powdered lenses: getting all the insulated powder / laque off the mount). With older bodies there are no contacts so older lenses can just be insulated or making contact without any difference.
06-14-2016, 07:52 AM   #34
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QuoteOriginally posted by bessa-66 Quote
I see. I that was only with old film lenses though. Good stuff anyway- I like the 300mm focal length!
To the best of my knowledge, focal length is a property of the lenses and does not change based upon which camera a lens is mounted.
How much of the image circle is used does change, hence the whole "crop factor" concept (something best forgotten before ever learning, IMHO).
Again to the best of my understanding, in this case what differentiates the digital APS-C lenses from full frame lenses is that the APS-C lenses are not claimed to make an image circle large enough to cover a full frame sensor.
In other words, it's just the size of the image circle and not the focal length that is different.

But, yeah, 300mm is nice.

06-14-2016, 09:58 AM - 1 Like   #35
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bessa-66

On your K 300mm ƒ4 the mount should have an aperture lever next to the small fin that sticks up. The lever should be to the right held there by a spring in the lens. You should be able to move that lever from right to left which will open the aperture from the smallest to the largest setting. Letting go of the lever it should spring back to the right which will stop the lens back down. I would guess this is what is causing the problem.
06-15-2016, 03:53 PM   #36
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QuoteOriginally posted by Rico Quote
bessa-66

On your K 300mm 4 the mount should have an aperture lever next to the small fin that sticks up. The lever should be to the right held there by a spring in the lens. You should be able to move that lever from right to left which will open the aperture from the smallest to the largest setting. Letting go of the lever it should spring back to the right which will stop the lens back down. I would guess this is what is causing the problem.
Hi Rico, it des that ok, but I can pull the lever off the little spring. My guess is the camera's aperture lever does this for some reason

---------- Post added 06-15-16 at 03:54 PM ----------

QuoteOriginally posted by Quartermaster James Quote
To the best of my knowledge, focal length is a property of the lenses and does not change based upon which camera a lens is mounted.
How much of the image circle is used does change, hence the whole "crop factor" concept (something best forgotten before ever learning, IMHO).
Again to the best of my understanding, in this case what differentiates the digital APS-C lenses from full frame lenses is that the APS-C lenses are not claimed to make an image circle large enough to cover a full frame sensor.
In other words, it's just the size of the image circle and not the focal length that is different.

But, yeah, 300mm is nice.
Oh I see. So THATS the difference! Why don't they just call it a 400mm lens then?
06-15-2016, 04:03 PM   #37
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QuoteOriginally posted by bessa-66 Quote
Oh I see. So THATS the difference! Why don't they just call it a 400mm lens then?
Not sure if you're pulling my leg.
If not, I apologize that my attempt was unclear.
06-16-2016, 02:18 AM   #38
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QuoteOriginally posted by Quartermaster James Quote
Not sure if you're pulling my leg.
If not, I apologize that my attempt was unclear.
You got me I was!!

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